A randomized controlled trial of the efficacy of a multifaceted counseling and support intervention for spouse- caregivers of Alzheimer's disease (AD) patients began at the NYU Silberstein Aging and Dementia Research Center (NYU-ADRC) in 1987. A sample of 406 spouse-caregivers (162 husbands and 244 wives) were assigned to either the intervention or a usual- contact control condition. All caregivers are regularly evaluated through home caregiving, nursing home placement, and post-bereavement phases of the caregiving career. The intervention postponed or prevented nursing home placement of AD patients, and minimized many negative consequences of caregiving. Preliminary results also suggest that the intervention leads to lower caregiver mortality. The project has been highly successful in recruiting and retaining study subjects, and in demonstrating the powerful impact of the intervention. More comprehensive longitudinal analyses are now proposed that will evaluate the mechanisms by which the intervention works. We propose to continue to follow all remaining research participants to the predetermined endpoint of the study: two years after the AD patient has died. We will continue to conduct regular assessments of caregiver functioning and AD patient status, and to provide counseling and support services for caregivers in the intervention group. This study is generating a unique longitudinal database. We have already recruited a large sample and have collected many years of data that carefully track the emotional well-being, physical health, and social support resources of spouse-caregivers. Continued funding is essential to complete the construction of this unique data base. In addition, we have forged collaborations with experts in longitudinal caregiving research and social support mechanisms. Latent growth modeling and structural equation modeling will be used to evaluate individual differences in caregiver functioning over time, to test for intervention effects, and to examine gender differences. Major outcome variables include caregiver depression, caregiver physical symptoms, patient institutionalization and caregiver and patient mortality. Change in social support and caregiver appraisals of patient behavior problems are hypothesized to mediate the impact of the intervention condition on these outcome variables. Findings from this study will enable health professionals and policy makers to reduce the socioeconomic impact of AD.